TALIF of Atomic Nitrogen in RF Plasma Source

Two-photon absorption laser-induced fluorescence (TALIF) was implemented to measure atomic nitrogen in a low-pressure RF plasma source. High-resolution wavelength scans across the 207 nm two-photon resonance revealed a well-defined spectral feature with a measured full-width half maximum (FWHM) of ~1.1 pm, from which we inferred a Doppler temperature consistent with the neutral population under these discharge conditions. Complementary saturation measurements of TALIF signal versus pulse energy exhibited the characteristic linear-to-plateau behavior expected for nitrogen TALIF. Together, these results demonstrate the viability of TALIF for probing atomic nitrogen in RF-driven plasmas and establish the baseline measurement capability required for future parametric studies.